I'm not sure Graphene's toxicity matters when a finished product it used internally, A device using graphene transistor equivalents will be bonded to a package's leadframe and encapsulated in a resin then mounted to a circuit board and then placed in an enclosure made of biocompatible plastics or titanium with a battery. That will then be placed in the body. It really is only the manufacturing processes and maybe the disposal methods that will be at issue. Disposal may be incineration so won't be a problem.

I did some work that required epoxy potting and we used silica powder as a stabiliser and economy filler and that is dangerous because the dust particles are so fine that they penetrate deep into the lungs. We used dust masks and fans for safety. Once potted there was no risk.

Even modern diesel engines make nanoscale particles of carbon compared to the 15-40um particles of older diesels. It's so fine that there's talk of lung cancer being an issue because it penetrates so deeply into the lungs.

So really what I'm saying is it's only when the materials are freely available as a nanoscale particle that they represent a risk, packaged parts really have no issue.

Look even at Beryllium oxide, used as a die insulator in RF transistors, yet extremely toxic.

The toxicity will mostly jeopardize the workers handling the powders, which for chemical vapor deposition (CVD) would be the fab workers in the bunny suits. Once the graphene is fixed in place with CVD on a substrate it should be safe--until the chips end of life when it comes apart in the landfill.

Thank you - it's hard to know how materials might affect us as there are so many threats short/long term - we have natural Asbestos in my area, and those prions from BSE and others scare the hell out of me.

Reg the Graphene - is it handled at all in a cell, or does it kill the cell, would the body remove the dead cell with the graphene in it - did I miss that in the article?

If graphine was made without the sharp edges could it be worn or broken/ablated, degraded by U/V or some other process to allow those edges to be recreated?

Whenever I hear about these new materials I alway am reminded of the Ringworld Series of books by Larry Niven.

As the graphene particles are exposing about the same shape as asbestos fibres: expect similar effects.Except when they are small enough to be absorbed. Then: switch to the effects of carbon-particulate matter.

The short-term effects were bad enough in a petri dish, hopefully we'll never know the long-term effects, but insted will engineering better methods of manfacturing graphene that eliminates its toxicity.

The researcher Agnes Kanes told me that their purpose was to make graphene safe for all types of applications, including medical implants, by engineering their properties to be non-toxic. In order to do so, her team had to first determine how graphene powders disruputs cell functions, which was the sharp corners. Their next step will be to engineer methods of eliminating the sharp corners that are piercing cell walls.